Thread gauge



Oct. 14, 19741. c. HECKER THREAD GAUGE Filed June 1e, 1959 2 Sheets-Sheet l w /ll 3 Inventor c .Gttornegs Oct. 14, 1941. c. HECKER THREAD GAUGE 2 Sheets-Sheet 2 Filed June 16, 1939 Patented Oct. 14, 1941 THREAD GAUGE Carl Hecker, Flint, Mich., assigner to General Motors Corporation, Detroit, Mich., a. corporation of Delaware Application June 16, 1939, Serial No. 279,429

11 Claims.

This invention relates to improvements in gauges for determining the pitch and the pitch diameter of threaded elements such as screws.

The ring gauges of the prior art havevbeen known and used to considerable extent, but it has been found that they are very tiresome on the hands of the operator after a short period of use, and this tiring of the operators hands has resulted in some unsatisfactory work inthe use of the gauges. The gauge of the invention may be used for the entire day and not be tiresome on the operator; it also enables the operator to check the taper or pitch angle of the threads, nicks in the threads, as well as the pitch diameter and pitch of the screw; and it enables the threaded elements to be checked at least twice as fast and with greater accuracy.

The gauge is adaptable to many different pitches and to screws having different pitch diameters. It is also possible to check, with one setting of the rolls, screws having the same pitch diameter but a diierent pitch or number of threads.

The essential mechanical feature of the gauge .is the mounting on a base of three cooperating spaced ribbed gauging rolls. Two of these three rolls are mounted in a stationary position, but the rolls are turnable on their axes. A manually operable slide is mounted on the base and in turn has a second slide mounted therein and on this second slide the third ribbed gauging roll is mounted in stationary position. Springs constantly urge both slides toward the stationary rolls and a limit stop is positioned on the base, between the slides and the stationary rolls, to limit the movement of the slides toward the stationaryl rolls. An adjustable indicating gauge is mounted'in the base and has its operating part in contact with the smaller slide and is operated thereby. A handle pivoted to the base is used for the manual operation of the slides.

On the drawings:

Figure 1 is a plan view of the thread gauge with a, part broken away better to show details of construction.

Figuresv 2, 3, 4, 5, and 6 are sectional views on the corresponding lines of Figure 1, Figure 3 being drawn on a larger scale.

Figure 7 is an end elevation of a part of Figure 1 looking in the direction of the arrows 1-1.

Figures 8 and 9 are details showing the same ribbed gauging rolls used to determine the pitch diameter of two dierent screws having a different number of threads, but which may or may not have the same outside diameter.

On the drawings, the numeral 2 indicates the thread gauge as a whole. The parts of the thread gauge are mounted on the base 4 which has a short at end 6 and a longer channel end 8. The channel end has the upstanding sides IIJ and I2 (Figure 6) these sides being shorter at the end of the gauge las indicated at I4 in Figure 2. The sides ID and I2 form a slideway I6- in which there is reciprocably received the slide I 8. The slide I8 has a cut-out or notch 20 at one side in which there is received the ball end 22 of a'handle 24 pivoted by -means oi a screw 26 to the side I2 of the base 4. The movement of the handle 24 will shift the slide I8 to the right in Figure l.

' The slide I8 is further provided with the two pins 28 which project downwardly into grooves 30 in the base. One coil spring 32 is positioned in each groove 3D and is'adjustable as to tension by means of the threaded element 34 having the coil spring 32. the tension on the spring 32 may be increased or decreased. The springs 32 are under compression and constantly press against the pins 28 to urge the slide I8 to the left in Figures 1, 2, and 5. These springs 32 have no effect on the work or screw to be gauged.

The slide I8 is provided with a slideway 38 in which a slide 40 is reciprocably mounted. This slide 48 has a pin 42 rigidly secured thereto and projects downwardly into a groove or channel 44 formed in the slide AI8. A coil spring 46 is received in the groove 44 and is positioned between the pin 42 `and the end of the groove and constantly urges the pin 42 and the slide 40 to the leftl when considering Figures 1, 2, and 5. The spring 46 is considerably weaker than the springs 32. This spring is always compressed the same amount regardless of the diameter of the work being gauged and acts to govern the tension against the work.

The top of the slide 40. is iiush with the top of the slide I8 as is best shown in Figure 6, and a cover plate 48 is positioned over both slides and secured to the sides I0 and I2 by means of the machine screws 50. t

One edge of the cover plate 48 is provided with a recess 52 to receive the ribbed gauging roll 54 when the slides I8 and 40 are moved to the right in -Figures 1 and 2. This roll 54 is mounted on the slide 40 in a xed position and the manner in which it is mounted is shown in Figure 2. The end of the slide 40 is tapered as indicated at 56 and is provided with an opening Iim which there is nxed `the bearing u. A post by means of the machine screws 88 threaded into the end of the ost 80. Equidistant from t e center line of the scre gauge, as shown in Figure'l, the end piece 10 has mounted thereon the two ribbed gauging rolls 80 and 92 and these rolls are mounted in the end piece in the identical manner as the roll 54 is mounted in the slide 40. The single ditierence in the mounting is that the` spacing washer 64a for the roll 90 and the corresponding spacing washer for the roll 92 are different in thickness from the spacing washer 64 for the gauging roll kil. Each successive spacer is slight- 1y thicker, and commencing with the spacing washer Sla the corresponding spacing washers for roll 92 will be a little thicker, while the spacing washer 64 will be thicker than the spacing washer for the roll 92. The reason for this difto the spiral angle of the thread of the screw or to the helix angle of the thread. Thee same eifect may be accomplished by providing shoulders on the posts 80, the shoulders being positioned where the washers 6| now are positioned and the one having a thickness different from the others.

The rol-l 54 is positioned on the Vcenterline of the gauge as shown in the plan view of Figure 1, while the rolls 90 and 82 are positioned equidistant on opposite sides of the center line so that when the parts are in the position shown in Figures 1 and 2 the rolls 54, 80 and 92 will be at the apices of a triangle and will be in posithe sides oi' the groove 18 to prevent the nut from turning. In the groove 14 there is positioned the shank of a distance spacer 8| the end of which is threaded into the nut 18. This spacer has the head 82 having openings 8l for the remay approach the end piece 1 0 may be changedA in order to set the screw gauge, i. e., change the spacing of the rolls. for screws of dinerent diameter. After the distance spacer ll has been put inplace the rolls lll. 98, and 92 are tested for f a rectangular extension 99 which nts into a ference in thickness is to accommodate the rolls er 88 to swing one way or the other to indicate groove |80 formed in the slide I8. The bottom of the slide beneath the groove |00 is hollowed out as indicated at |82 and a slot |04 is formed in the bottom of the hollowed out part to allow communication with the groove |08. :A set screw |98 passes through the groove l and is screwed into the extension 99 rigidly to hold the gauge 98 'in adjusted position.

The casing of the gauge 9! has an extension arm |88 which acts as a bearing for an operating member IIO. 'having a-head H2 which abuts against the 'end of the slide 4l.

In the position of the parts'as shown in Figures 1 and 2, if the screw is true in all respectsv the pointer 98 will register zero on the scale and any deviation in the threads will cause the pointthe degree of inaccuracy of the threads. The indicating gauge 98 may be graduated to read in thousandths orten thousandths of an inch.

Referring to Figure 3 there is shown an enlarged view o! the roll 54 and the position it takes when in contact with the screw M to be tion to gauge the pitch diameter and pitch-of a L ception of av suitable tool or handle yto enable the turning of. the distance spacer to enable its removaL 0n the head 82 there is the extension 88 which is adapted to strike against a block 88 formed as an e tension on the slide il. The distance between the tip' of the extension 8lv to the adjacent edge of the end piece 10 is dednitely predetermined and will determine the extent to which. the slide ,Il may move toward the end piece; or, in other words, will allow the slide gauged. The roll 54 is provided with the ring ribs llland each rib lll is provided with a plated surface IIB, the plating beingA preferably with chromium.' The threads have a broad base and a tapered outer part. 'Ihe tip of th outer part is flattened as indicated at II1. 'Inasmuch as all oi! the 'rolls are alike, the description of one will suillce for the three.

Figure 4 shows the position of the two rolls 88 and 54 in contact with the screw Il.' In this view it willy be noted that the thread III of the roll M is a little higher than the rib Ill of the roll 9Il.l This is caused by the dierence in thickness of the spacers 84a and Il, and is `made neccessary because of the change in the helix angle of the thread on the screw 9|.

In Figures 8 and 9 there is illustrated a modifled form of roll 'and there is illustratedthe manner in which these rolls may be used to check on screw threaded elements Ma' and Mb which-'may be the same or a different pitch diameter but have a different number oi threads I8 to be moved/to a denite stopjposition. or within a i'ew thousandths of an inch of the pitch diameter ofthe screw yto be measured; The' center slide will then move the same distance when gauging the work and the spring .It will -receive the same amount oi. compression.' By 4' removing one distance spacer and replacing it with another, the?? extent to whlchthe slide I8 or a different pitch. 'The ribs Ill on the rolls 54'. are so spaced that both'screws lla and b may be measured with the same setting although they have a different number of. for the reason that the spacing of the ribs Ill oi' the rolls allows them to nt between the threads of the elements a and lib becausethethreads of the two are a 'convenient and suitable multiple of each gother. For instance, i! screw a has a pitch ofv 18 while'the pitch of screw [Ib is-32, eitherscrews of a 18 or 92 pitch may be .measured from 'th'e'same setting. Similarly. `screws having a-20 and 28l pitch Vmay be measwere 4used for, the 18 a different pitch diameter, the distance spacer BI must be changed to give a spacing in accordance with the pitch diameter of the screw. A setting master or spacer 8| is required for each pitch diameter.

I claim:

1. In a screw thread gauging device, a base, a plurality of circumferentially ribbed gauging rolls mounted on the base, a slide mounted on the base, means constantly urging the slide toward the rolls, means to limit the sliding movement of the slide toward the rolls, a second slide mounted in the first slide, afcircumferentially ribbed gauging roll mounted on said second slide and adapted to cooperate with the plurality of rolls on the base to determine the pitch of the threads, means constantly urging said second slide toward 'the stationary rolls, an indicating gauge mounted on the first slide and operable by the second slide, and manual means to withdraw the first slide from the stationary rolls to enable the insertion of a screw.

2. In a screw thread gauging device, a base, a plurality of rotatable circumferentially ribbed gauging rolls mounted in a stationary position on the base, a slide mounted in a slideway on the base, said slide reciprocable to and from the rolls, removable and replaceable means to limit the movement of the slide toward the rolls, a second slide mounted in the rst slide, a rotatable circumferentially ribbed gauging roll mounted in a xed position on the second slide,` the adjacent ribs of each roll being in different parallel planes to determine the pitch of the thread of a screw, manual means to reciprocate the first mentioned slide, an indicating gauge mounted in a stationary position on the firstmentioned slide, said gauge operable by the second mentioned slide.

3. In a screw thread gauging device, a base, a plurality of rotatable circumferentially ribbed gauging rolls mounted on spaced parallel axes in a stationary position on the base, each roll' being mounted on a diierent axis, a slide, a third rotatable circumferentially ribbed gauging roll mounted in a stationary position on the slide and adapted to cooperate with the other rolls to gauge the thread of the screw, means to limit the sliding movement of the slide toward the plurality of rolls, an indicating gauge mounted in a fixed position on and adapted to be operated Where it is desired to measure screws having circumferentially ribbed gauging rolls mounted in xed positions on the end piece, a slide mounted on the base for movement to, and from the end piece, means constantly urging said slide toward the rolls, means secured to the end piece to limit the movement of the slide toward the rolls, a second slide mounted in the first slide,

meansconstantiy urging the second slide toward the rolls, a circumferentially ribbed gauging roll rotatably mounted in a xed position on the second slide, said slidel roll cooperable with the two end-piece rollsto determine the pitch of the thread of a screw, manual means to reciprocate the slides, an indicating gauge mounted on4 and operated with the second slide, said indicating gauge giving a direct reading of the amount of deviation of a screw from a standard thread.

.6. In a screw thread gauging device, a base,

an end piece secured to the base, two rotatable circumferentially ribbed gauging rolls mounted in fixed positions on the end piece, a slide mounted on the basefor movement to and from the end'piece, removable and reciprocable means secured to the end piece to limit the movement of the slide toward the rolls, a second slide mounted in the first slide, a circumferentially ribbed gauging roll rotatably mounted in a fixed position on the ksecond slide, said slide roll cooperable with the two end-piece rolls to determine the pitch of the thread of a screw, manual means to reciprocate the slides, an indicating gauge mounted on and operated with the second slide, said indicating gauge giving a direct reading of the amount of deviation of a screw from a standard thread.

, 7. In a screw thread gauging device, a base,

two stationary rotatable circumferentially ribbed gauging rolls mounted on spaced parallel. axes at one end of the base, a slide mounted on the base, `means to reciprocate the slide to and from the rolls, a third roll movably mounted on the slide and adapted to cooperate with the two stationary rolls, said third roll being mounted on an axis parallel with the axis of the other two rolls, means to limit the movement of the'slide toward the two stationary rolls, an indicating gauge .rigidly mounted on the slide, the operation of 'with the slide, and means `manually to operate f the slide to separate the third roll from the plubetween the rolls.

4. In a screw thread gauging device, a base, an end piece secured to the base, two rotatable circumferentially ribbed gauging rolls mounted in xed positions on the end piece, a slide mounted on the base for movement to and from the end piece, means secured to the end piece to limit the movement of the slide toward the rolls, a second slide mounted in the first slide, a circumferentially ribbed gauging roll rotatably mounted in a fixed position on the second slide, said slide roll cooperable with the two end-piece rolls to determine the pitch of the thread of a screw, manual means to reciprocate the slides, an indicating gauge mounted on and operated with the second slide, said indicating gauge giving a direct reading of the amount of deviation of a screw to be gauged from a standard thread.

5. In a screw thread gauging device, a base,

an end piece secured to the base, two rotatable said indicating gauge depending upon the movement of the moving roll, said gauge giving the direct reading of the accuracy of the screw thread.

8. In' a screw thread gauging device, a base, two stationary rotatable circumferentially ribbed gauging rolls mounted on spaced axes at one end of the base, a slide .mounted on the base, means to reciprocate the slide to and from the rolls, a third roll movably mounted on the slide and adapted to cooperate with the two stationary rolls, means to enable a relative movement between the slide andthe third roll, means to limit the movement of the slide toward the two stationary rolls, an indicating gauge rigidly mounted on the slide, the operation of said in-y dicating `gauge depending vvupon the movement ofv the moving roll relative to the slide, said gauge giving the direct reading of the accuracy of the screw thread.

9. In a screw thread gauging device, a base, two stationary rotatable circumferentially ribbed gauging rolls mounted at one end of the base, a slide mounted on the-base for reciprocation to andfrom the rolls, means to llimit the movement of the slide toward the rolls, a second slide` mounted for reciprocable movement on the rst slide, a third circumierentially ribbed gauging roll mounted in the second slide, an indicating gauge adjustably mounted in the first slide and operated by the second slide, said gauge giving a direct reading of the accuracy of the screw thread.

10. In a screw thread gauging device, a base, two-stationary rotatable circumferentially ribbed gauging rolls mounted at one end of the base, a slide mounted lon the base i'or reciprocation-to and from the rolls, means constantly urging said slide toward the rolls, means to limit the movement of the slide toward the rolls. a second slideV mounted for reciprocable movement on the iirst slide, means constantly urging said second slide toward the rolls, a third circumferentially ribbed gauging roll mounted' in the second slide, an indicating -gauge adjustabiy mounted in the rst slide and'operated by the second slide, said` gauge giving a direct reading oi 11. In a screw thread gauging device, a base. two gauging rolls rotatably and removably mounted in stationary positions on the base, a third rotatable gauging roll, a plurality oi movable means to mount the third roll on the base for movement to and from the stationary rolls, a plurality of circumferential ribs on each roll, means on the base and enga-geable with the mounting means for the third roll to limit the movement ofthe mounting means and third roll, said means limiting the movement in accordance with the size oi.' the screw to be gauged, the three rolls adapted to receive a screw therebetween to determine the pitch thereof, and an indicating gauge mounted in a stationary position on one of said movable means, said pluralitynf of the third roll.

CARL HECKER. 

